Furnace unit



Patented Aug. 5, 1941 U ITED-STA S PATENT OFFICE l $251,380

FURNACE Ralph Wat-render, Sharon, Pa.

Application sums, 1940, Serial No. 250,924

. 40mm; Thi invention relates to a furnace unit. The principal object of the invention is the provision ofa furnace unit adapted to suitably v vision of a furnace unit adapted to suitably heat cylindrical objects the whole of which is so formed that the atmosphere withinthe furnace unit may be evacuated and a suitable controlled atmosphere substituted therefor.

A further object of theinvention is the provision of a furnace unit incorporatingthe use of a cylindrical carbon resistance heater spaced gases from a single pump and gas source thus providing for a greater production rate than would otherwise be possible;

with the foregoing and other objects in view.

which will appear as the -description proceeds,

the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it

. being understood that changes in the precise and positioned between upper and lower metallic conductors, wherein the structure of the lower metallic conductor also forms a portion of a closure completely enclosing the cylindrical resistance heater and any tubular material which may be placed thereover. r

A still further object of the invention is the provision of a furnace unit utilizing a cylindrical resistance heater, the necessary electrical conductors for the same being so formed as to permit tubular objects to be slipped downwardly over the said cylindrical resistance heater.

The furnace unit shown and described herein has been designed to provide a unit suitable for effectively heating tubular metal objects to which various other metal form are being affixed through a bonding action, such as an article disclosed in my co-pending application for patent, Serial Number 321,649, filed March 1, 1940. In order that the oxidizing effect of conventional atmosphere be avoided, the furnace unit is so constructed that the essential working portions thereof are completely enclosed and subject to evacuation of undesirable atmosphere so that a desirableatmosphere-may be introduced thereinto, which desirable atmosphere would com-' prise such gases as may be needed for a satisfactory fiuxing action in connection with the bonding of various metal sections to the tubular object positioned about the heater tube of the furnace. The furnace unit is so formed that a plurality of the units may be positioned on a suitable circular platform and electrically connected in desirable working rotation to a centrally located transformer thus permitting a number of cylindrical object to be bonded in a number of individual furnace units all of which may be evacuated and supplied with desirable embodiment of the invention herein disclosed, can be made within the scope of what is claimed githout departing from the spirit of the inven- 'I'he invention is illustrated in the accompanying drawing wherein:

Figure 1 is a cross sectional side elevation of the furnace unit on line 'l--| of Figure 2.

Figure 2 is a cross sectional elevation taken on lines 2-2 of Figure 1.

By referring to the drawing and Figure 1 in particular it will be seen that the furnace unit comprises a base It formed with an annular fluid cooling chamber ll therein and provided with a centrally positioned opening I! through which there is adapted to be positioned a tubular metallic conductor IS, the uppermost portion of which extends some distance above the base In and which is provided with a hollow circular conductor H so-formed that a cylindrical carbon resistance heater it may be positioned between the same and the base It in a manner so that a suitable electric circuit directed through the tubular conductor l3 and circular conductor H andbase ill will bring the cylindrical resistance heater ii to incandescent heat due to the resistance thereof to the electric current. In order that the cylindrical resistance heater l5 may be accurately and satisfactorily positioned between the base It and the circular conductor It a matching pair of opposed annular grooves l 6 and I! are formed in the conductor I 4 and base ill respectively. The lowermost portion of the tubular conductor I3 is preferably threaded as indicated by the numeral i8 for the reception of a suitably shaped threaded nut I9 which in turn rests against thebottom of the base it through a suitable metallic washer 20 and an insulating washer 2|. Thus the cylindrical resistance heater I5 may be firmly positioned between the circular conductor I4 and the base ill by suitable tightening of the nut I9. It isobvious that there is sufficient clearance provided between the exterior surfaces of the tubular conductor i3 and the interior surfaces of the centrally positioned opening l2 to prevent a short circuiting of the furnace circuits at this point.

In order that the tubular conductor l3 and the circular conductor it may be suitably fluid cooled to overcome the effects of the heat of the cylindrical resistance heater IS, a vertically positioned fluid tube 22 is positioned within the tubular conductor l3 and a tubular cross head 23 communicates therewith in the space within the hollow circular conductor l4 so that adequate circulation of fluid therethrough is insured as cooling fluid introduced through the vertically positioned tube 22 will be forced upwardly therethrough and outwardly of the tubular cross head 23 so as to cool the circular conductor i4. There is a sufficient clearance between the conductors l3 and ll and the cooling fiuid tubes 22 and 23 to provide an adequate return channel for the cooling fluid and an outlet 24 is provided at the bottom of the tubular conductor H which communicates through asection of suitable fluid conductor 25 with an inlet 26 opening into the annular cooling fluid channel ll within the base ID from which a suitable outlet 21 is provided. In order that a cylindrical object to be heat treated may be accurately positioned about the cylindrical resistance heater l5, an annular groove 28 is provided immediately adjacent to'and outside of the annular groove ii in the base 10 so that a cylindrical object positioned downwardly over the circular conductor l4 and cylindrical resistance heater IE will rest therein in desirable spaced relation to the said conductor and heater. In this connection it may be pointed out that any tendency of the tubular object being heat treated to be attracted to the resistance heater l or conductor l4 may necessitate the use oi! an insulating collar positioned around the uppermost portion of the heater l5 or the conductor l4 and between the same and the tubular object being treated, or the collar might be positioned about the upper surface of the tubular object.

In order that the heating operation may be conducted in a desirable atmosphere the base Iii is provided with an annular shoulder 29 adapted to receive in an air tight manner the lower exremities of a cover 30 which is of a size and shape sufficient to satisfactorily enclose the furnace unit and the material being treated thereon. In order that a desirable atmosphere may be introduced within this enclosure, suitable communication openings 3i and 32 provide for the evacuation of the undesirable atmosphere and the introduction of a desirable atmosphere within the enclosure. It will thus be seen; by referring to the drawing, that a tubular metal object such as an interna combustion engine cylinder to which a plurality of heat radiating fins are to be afflxed may be readily slipped downwardly over the con\ ductor i l and cylindrical resistance heater 15 so that the lowermost portions of the same will rest in the annular groove 23 and that in that position the cover 3E; installed and the enclosed area be evacuated and a desirable gas subsequently introduced thereinto at which time suitable electrical connections may be established between the base i0 and the tubular conductor 13 which will 'result in an incandescent temperature of the nace unit makes possible the practical bonding of such articles primarily due to the capability of supplying a satisfactory atmosphere for the bonding operation as this eliminates the impurities commonly existing in normal atmosphere from being absorbed in the bond and thus effecting the satisfactory bonding of the various metal parts.

What I claim is:

1. In an electric furnace the combination of a gas tight cover having a supporting base member having an opening therein, the said base member serving as a conductor, and a cylindrical resistance heater positioned on the said base member within the said cover by means of an electrode of T shaped cross section positioned axially through the said opening and resistance heater and adapted to clamp the resistance heater against the said base.

2. In an electric furnace unit the combination of a gas tight container and a tubular resistance heater positioned therein, the said container comprising a base and a cover adapted to fit thereover, the said base having an opening formed therein, a conductor of T shaped cross section positioned in the said opening and adapted to clamp the said tubular resistance heater against the said base, the said conductor and base forming means through which the said resistance heater may be energized.

3. In an electric furnace the combination of an air tight enclosure comprising a cover and a base and a cylindrical resistance member positioned on the said base within the enclosure, the said base forming an electrical conductor, a secondary electrical conductor positioned in a gas tight manner through an opening in the said base and provided at its uppermost end with an enlarged section, the said enlarged section of the secondary conductor adapted to contact the top of the said cylindrical resistance member and hold it in contact with the said base.

4. In an electric furnace comprising a gas tight container and a cylindrical resistance heater positioned therein, the said gas tight container formed of a base and a cover, the said base having an opening therein, the said cylindrical resistance heater positioned on the said base so as to encircle the said opening and clamped against the said base by means oi a conductor positioned vertically through the said opening and resistance heater and adapted to engage the top of the said cylindrical resistance heater, together with means for evacuating the area within the said gas tight enclosure and for introducing a desirable atmosphere thereinto.

RALPH WARRENDER. 

